docs: def tag_pos_volume(line):
      """Tag POS volume number
  
      POS is journal that has special volume numbers
      e.g. PoS LAT2007 (2007) 369
      """
      def tagger(match):
          groups = match.groupdict()
          try:
              year = match.group('year')
          except IndexError:
              # Extract year from volume name
              # which should always include the year
              g = re.search(re_pos_year_num, match.group(
                  'volume_num'), re.UNICODE)
              year = g.group(0)
  
          if year:
              groups[
                  'year'] = ' <cds.YR>(%s)</cds.YR>' % year.strip().strip('()')
          else:
              groups['year'] = ''
  
          return '<cds.JOURNAL>PoS</cds.JOURNAL>' \
              ' <cds.VOL>%(volume_name)s%(volume_num)s</cds.VOL>' \
              '%(year)s' \
              ' <cds.PG>%(page)s</cds.PG>' % groups
  
      for p in re_pos:
          line = p.sub(tagger, line)
  
      return line